Today, the recommendations endpoint only accepts a single shift per request. Getting recommendations for multiple unassigned shifts requires making separate API calls for each one, which is inefficient and adds unnecessary latency for clients managing larger sets of open shifts.

The request is to support submitting multiple shifts in a single recommendations call, with results returned per shift. This would also unlock a "which shift to assign next" use case, where results are ordered globally across all submitted shifts rather than per shift individually.